PZL.4
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| PZL.4 | |
|---|---|
| Type | Passenger aircraft |
| Manufacturer | PZL |
| Maiden flight | 8 January 1932 |
| Introduced | 1933 |
| Retired | 1936 |
| Status | prototype |
| Primary user | Polish civilian aviation (LOT Polish Airlines) |
| Number built | 1 |
The PZL.4 was a Polish three-engine passenger aircraft for 10 passengers, built in PZL factory in 1932, which remained a prototype. It was the first Polish-designed and produced multiengine plane.
Contents |
[edit] Development
In spite of buying a party of three-engine Fokker F.VIIb/3m aircraft, LOT Polish Airlines soon started looking for more modern design and organized a design contest in 1928. The contest was won by the Polish engineer Zygmunt Bruner, working in the French Bernard works, with his design T-600. It was all-metal high-wing three-engine monoplane, similar to Ford Trimotor. State Aviation Works PZL decided to take over its development, and a group of engineers was sent to Paris and worked the design in 1929, under direction of Zygmunt Bruner. There were also carried out aerodynamical trials of a plane model. Detailed technical drawings were worked in PZL in Warsaw in 1930, under direction of Stanisław Prauss, and a prototype was built, designated PZL.4 (this designation was used before for a single-engine design worked out for a passenger plane contest in 1928, won by PWS-20).
The prototype was flown on 8 January 1932 in Warsaw by Bolesław Orliński (markings SP-AGY). In June 1932 it took part in an international air meeting in Warsaw. From autumn 1932 to 1935 it was evaluated by LOT Polish Airlines, but it was found unsatisfactory. The empty weight was bigger by 730 kg, than designed, what decreased performance. As a result, its performance was inferior to Fokker F.VIIb/3m, with the same engines. Proposal of installing Gnome-Rhone K-7 300 hp or Pratt-Whitney Wasp 450 hp engines were rejected by LOT (the latter engines would demand strengthening of construction).
The prototype was withdrawn from service in 1936 and scrapped in 1937.
[edit] Description
High-wing cantilever monoplane of metal construction, with closed cab and three engines. A fuselage rectangular in cross-section, made of duralumin, covered with duralumin sheet. Duralumin wing with rounded endings, two-spar, covered with Wibault-pattern ribbed duralumin sheet, the same tailfins. Crew of two (pilot and mechanic), in a cab in front, before the wing, with twin controls. Next and slightly below in a fuselage, under the wing, there was a cabin for 10 passengers in three compartments. The cabin had wide rectangular windows, slopped outwards for a better view, and door on the left side. The cabin had places for a baggage behind it and below a floor.
Three 9-cylinder radial engines Wright Whirlwind J5 in the fuselage front and in wing nacelles (240 hp take-off power, 220 hp nominal power, produced by the Polish Skoda Works division). Engines were fitted with Townend rings. Three-blade metal propellers, later two-blade wooden propellers of a fixed pitch. Conventional fixed landing gear, with a rear wheel, main gear wheels' diameter 1.15 m. Fuel tanks 915 l in central wing section (cruise fuel consumption 180 l/h).
[edit] Specifications
General characteristics
- Crew: 2, pilot and mechanic
- Capacity: 10
- Length: 16.5 m ()
- Wingspan: 24.4 m ()
- Height: 3.3 m ()
- Wing area: 77 m² (ft²)
- Empty weight: 4081 kg ()
- Loaded weight: 5586 kg ()
- Useful load: 1505 kg ()
- Powerplant: 3× Wright Whirlwind J5 air-cooled 9-cylinder radial, 240 hp () each
Performance
- Maximum speed: 190 km/h
- Cruise speed: 170 km/h
- Stall speed: <105 km/h ()
- Range: 800 km ()
- Service ceiling 2800 m ()
- Rate of climb: 2.3 m/s ()
- Wing loading: 72.6 kg/m² ()
[edit] References
- Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939" (Polish aviation constructions 1893-1939), WKiŁ, Warsaw 1977 (Polish language, no ISBN)
[edit] See also
Comparable aircraft
[edit] External links
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